Improving Human-Robot Cooperation and Safety In The Shared Automated Workplace

Modern industries take advantage of human-robot interaction to facilitate better manufacturing processes, particularly in applications where a human is working in a shared workplace with robots. In manufacturing settings where separation barriers, such as fences, are not used to protect human workers, approaches should be implemented for guaranteeing human safety. Despite existing methods, which define specifications and scenarios for human-robot cooperation in industry, new approaches are needed to provide a safer workplace while enhancing productivity. This thesis provides collision-free techniques for safe human-robot collaboration in an industrial setting. Human-robot interaction in the industry is studied to develop novel solutions and provide a secure and productive industrial environment. Providing a safe distance between a human worker and a manipulating robot, to prevent a collision, is an important subject of this work. This thesis presents a safe workplace by proposing an effective human-tracking method using a sensor network. The proposed technique utilizes a non-linear Kalman filter and Gaussian optimization to reduce the risk of collision between humans and robots. In this regard, selecting the most sensitive sensors to update the Kalman filter’s gain in a noisy environment is crucial. To this end, reliable sensor selection schemes are investigated, and a strategy based on multi-objective optimization is implemented.Finally, safe human-robot cooperation is investigated where humans work close to the robot or directly manipulate it in a shared task. In this case, the human’s hand is the most vulnerable limb and should be protected to achieve safe interaction. In this thesis, force myography (FMG) is used to detect the human hand activities to recognize hand gestures, detect the exerted force by a worker\u27s hand, and predict human intention. This information is then used to control the robot parameters, such as the gripper’s force. Furthermore, a human intention prediction scheme using FMG features and based on recurrent neural network (RNN) topology is proposed, to ensure safety during several industrial collaboration scenarios.The validity of the proposed approaches and the performance of the suggested control techniques are demonstrated through extensive simulation and practical experimentation. The results show that the proposed approaches will reduce the collision risk in human-robo

Novel Bidirectional Body - Machine Interface to Control Upper Limb Prosthesis

Objective. The journey of a bionic prosthetic user is characterized by the opportunities and limitations involved in adopting a device (the prosthesis) that should enable activities of daily living (ADL). Within this context, experiencing a bionic hand as a functional (and, possibly, embodied) limb constitutes the premise for mitigating the risk of its abandonment through the continuous use of the device. To achieve such a result, different aspects must be considered for making the artificial limb an effective support for carrying out ADLs. Among them, intuitive and robust control is fundamental to improving amputees’ quality of life using upper limb prostheses. Still, as artificial proprioception is essential to perceive the prosthesis movement without constant visual attention, a good control framework may not be enough to restore practical functionality to the limb. To overcome this, bidirectional communication between the user and the prosthesis has been recently introduced and is a requirement of utmost importance in developing prosthetic hands. Indeed, closing the control loop between the user and a prosthesis by providing artificial sensory feedback is a fundamental step towards the complete restoration of the lost sensory-motor functions. Within my PhD work, I proposed the development of a more controllable and sensitive human-like hand prosthesis, i.e., the Hannes prosthetic hand, to improve its usability and effectiveness. Approach. To achieve the objectives of this thesis work, I developed a modular and scalable software and firmware architecture to control the Hannes prosthetic multi-Degree of Freedom (DoF) system and to fit all users’ needs (hand aperture, wrist rotation, and wrist flexion in different combinations). On top of this, I developed several Pattern Recognition (PR) algorithms to translate electromyographic (EMG) activity into complex movements. However, stability and repeatability were still unmet requirements in multi-DoF upper limb systems; hence, I started by investigating different strategies to produce a more robust control. To do this, EMG signals were collected from trans-radial amputees using an array of up to six sensors placed over the skin. Secondly, I developed a vibrotactile system to implement haptic feedback to restore proprioception and create a bidirectional connection between the user and the prosthesis. Similarly, I implemented an object stiffness detection to restore tactile sensation able to connect the user with the external word. This closed-loop control between EMG and vibration feedback is essential to implementing a Bidirectional Body - Machine Interface to impact amputees’ daily life strongly. For each of these three activities: (i) implementation of robust pattern recognition control algorithms, (ii) restoration of proprioception, and (iii) restoration of the feeling of the grasped object's stiffness, I performed a study where data from healthy subjects and amputees was collected, in order to demonstrate the efficacy and usability of my implementations. In each study, I evaluated both the algorithms and the subjects’ ability to use the prosthesis by means of the F1Score parameter (offline) and the Target Achievement Control test-TAC (online). With this test, I analyzed the error rate, path efficiency, and time efficiency in completing different tasks. Main results. Among the several tested methods for Pattern Recognition, the Non-Linear Logistic Regression (NLR) resulted to be the best algorithm in terms of F1Score (99%, robustness), whereas the minimum number of electrodes needed for its functioning was determined to be 4 in the conducted offline analyses. Further, I demonstrated that its low computational burden allowed its implementation and integration on a microcontroller running at a sampling frequency of 300Hz (efficiency). Finally, the online implementation allowed the subject to simultaneously control the Hannes prosthesis DoFs, in a bioinspired and human-like way. In addition, I performed further tests with the same NLR-based control by endowing it with closed-loop proprioceptive feedback. In this scenario, the results achieved during the TAC test obtained an error rate of 15% and a path efficiency of 60% in experiments where no sources of information were available (no visual and no audio feedback). Such results demonstrated an improvement in the controllability of the system with an impact on user experience. Significance. The obtained results confirmed the hypothesis of improving robustness and efficiency of a prosthetic control thanks to of the implemented closed-loop approach. The bidirectional communication between the user and the prosthesis is capable to restore the loss of sensory functionality, with promising implications on direct translation in the clinical practice

Computational Intelligence in Electromyography Analysis

Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG may be used clinically for the diagnosis of neuromuscular problems and for assessing biomechanical and motor control deficits and other functional disorders. Furthermore, it can be used as a control signal for interfacing with orthotic and/or prosthetic devices or other rehabilitation assists. This book presents an updated overview of signal processing applications and recent developments in EMG from a number of diverse aspects and various applications in clinical and experimental research. It will provide readers with a detailed introduction to EMG signal processing techniques and applications, while presenting several new results and explanation of existing algorithms. This book is organized into 18 chapters, covering the current theoretical and practical approaches of EMG research

Controlling robot gripper force by transferring human forearm stiffness using force myography

This paper presents an approach for human-robot cooperation by transferring human forearm stiffness to the robot. The essential element of the proposed approach is Force Myography (FMG) of the forearm muscles that provides the robot with the human arm stiffness while picking up a part. Through this framework, the robot controller can adapt its gripper force to imitate human behavior facing different parts in weights and sizes during the cooperation. The proposed method is evaluated experimentally in picking-up and moving the pieces tasks that are common activities in industries. The results demonstrate that the robot can control its arm gripper force facing different parts with the error less than 2%, that depicts the effectiveness of the proposed method

WOFEX 2021 : 19th annual workshop, Ostrava, 1th September 2021 : proceedings of papers

The workshop WOFEX 2021 (PhD workshop of Faculty of Electrical Engineer-ing and Computer Science) was held on September 1st September 2021 at the VSB – Technical University of Ostrava. The workshop offers an opportunity for students to meet and share their research experiences, to discover commonalities in research and studentship, and to foster a collaborative environment for joint problem solving. PhD students are encouraged to attend in order to ensure a broad, unconfined discussion. In that view, this workshop is intended for students and researchers of this faculty offering opportunities to meet new colleagues.Ostrav